What it is, how it works and why it may not succeed

You've heard the term and probably read stories about smart homes where the toaster talks to the smoke detector. But what makes it all connect? When will it become mainstream, and will it work? These frequently asked questions help explain it all.

What is the Internet of Things?

There is no agreed-upon definition, but there is a test for determining whether something is part of the IoT: Does one vendor's product work with another's? Does a door lock by one vendor communicate with a light switch by another vendor, and do you want the thermostat to be part of the conversation?

Here's the scenario: As you approach the front door of your house, a remote control built into your key unlocks the door. The door's wireless radio messages the network, which prompts the hall light to turn on. The house thermostat, which was lowered after you left for work, returns to a comfort zone. Everything is acting in concert, which brings us to the elegant definition of IoT by Paul Williamson, director of low power wireless for semiconductor maker CSR: "A true Internet of Things is coordination between multiple devices."

What makes the Internet of Things almost human?

In a word: Sensors. Many IoT devices have sensors that can register changes in temperature, light, pressure, sound and motion. They are your eyes and ears to what's going on the world. Before we talk about what they do, let's describe them. These sensors are part of a device category called a microelectromechanical system (MEMS) and are manufactured in much the same way microprocessors are manufactured, through a lithography process. These sensors can be paired with an application-specific integrated circuit or an ASIC. This is a circuit with a limited degree of programming capability and is hardwired to do something specific. It can also be paired with microprocessor and will likely be attached to a wireless radio for communications.

Can you give an example of how IoT sensors work?

Here's the scene: You are away on vacation and the house is empty. A moisture sensor detects water on the basement floor. That sensor finding is processed by an app, which has received another report from a temperature sensor that detects the flow of water in the main water pipe. (When water flows, it takes away heat and lowers the temperature).

That both sensors are detecting anomalies is cause for concern. A high rate of flowing water may signal a burst pipe, triggering an automated valve shutoff; a slight water flow might be a running toilet, and the water on the basement floor by routine leakage from a heavy rain. In either case, you get a machine-generated message describing the findings.

Here's how you investigate. Via a mobile app, you get two one-time codes to unlock your front door, one for your neighbor and another for a plumber. When the door is unlocked, a text alert tells you who entered. Having knowledge of the condition of your home may be a big driver of IoT adoption.

How will IoT sensors work in public spaces?

Take parking. Cities are embedding sensors in on-street parking spaces from a company called Streetline that can detect if a car is parked in one. Drivers looking for a parking space use the company's mobile app, which lets them know when a space becomes available. Streetline has also added sound level and surface temperature sensors to help cities determine the best times to apply salt and use noise sensors to ensure compliance with ordinances.

In the public arena, a smartphone can double as a sensor. In Boston, as people drive down a road, the phone's accelerometer sensor will keep track of bumps. An accelerometer can tell up from down, but more precisely it measures acceleration. All it took to turn a smartphone into a road condition monitoring tool, was an app that used its existing sensor in a new way.